eChapters

PESTS OF CEREALS

Rice (Oryza sativa)

Rice is the staple food of a vast majority of people throughout the world, especially in India. Rice crop is grown in about 75 million acres, which is about one-third of the total world area under rice. The warm and humid environment for the rice crop is best suited for invasion by several insect pests and as many as 85 species of insects are known to infest this crop. The damages caused by different pests extend from the seedling to harvest stages of the crop. Some of these pests are widely distributed and cause extensive damage. The more important pests are described below:

1. Rice stem borer or Rice yellow stem borer

Scirpophaga (Tryporyza) incertulas

Order - Lepidoptera

Family - Pyraustidae

Among the pests, which ravage rice crop, ‘rice stem borer’ is a major one and infests rice crop at all growth stages, from seedling to flowering. It is a specific pest of rice alone and is more serious during the months of October-January. The pest has a wide distribution in all Asian countries. The damages caused by this pest ranges from 5-20 per cent. Generally, late varieties of rice are more severely infested than the early maturing varieties, because of the possibility of the pest multiplying in larger numbers by the time the late varieties come to maturity. Cold weather with high humidity and low temperature prevalent during October-December is found to be conducive for the multiplication of the insect.

Mango (Mangifera indica)

1. Mango hoppers

(i) Amritodes atkinsoni (ii) Idioscopus niveosparsus and (iii) I. clypealis

Order - Hemiptera

Suborder - Homoptera

Family - Cicadellidae

Nature of damage. Three different species of hoppers are found to cause damage to mango trees. During some years, especially during the months of November-February, when the mango trees come to flowering, the pest appears in large numbers. During the other months, the pests are seen in much lesser numbers in an active form, while the other insects hibernate under the bark of the trees. Even in the peak period of pest occurrence, after a few heavy showers, the number of insects is considerably reduced.

During the cold season, when the trees put out the flower spikes, thousands of hoppers, young and adults appear in large numbers, pierce, suck and feed on the sap from the tender shoots, flower stalks, flowers and buds. This drain of the sap causes the buds and flowers to dry, wither and they are shed in large numbers, as a result fruit production may go down by 25-60 per cent. When a severely infested tree is approached, thousands of hoppers hop or fly about and make a rustling noise, as they dash against the foliage. The hoppers exude a sweet, sticky fluid excretion and this fluid thrown out by myriads of these insects after feeding on the tree sap, wets the soil underneath the trees and on the surface of the leaves of the trees. In case of severe infestation, the fluid may fall down in drops. The secretion attracts scores of flies, bees and other insects, which come to feed on the secretion. The infested tree presents a sickly appearance. The trees get devoid of buds and blossoms. The leaves appear shiny and are covered by ‘sooty mould’, a fungal disease. Thousands of caste skins of the nymphs are found on the shoots and leaves. The continuous damage caused to the trees year after year by the pest makes them loose their vigor gradually and eventually leads to severe reduction in their yielding capacity.

Life cycle of the pest. The female hopper inserts spherical, pale whitish eggs singly into the plant tissues through slits made in the young shoots, flower stalks and flower spikes. The eggs hatch in 4-6 days and the young nymph hatching out of the egg looks quite similar to the adult. The nymphs are very active and move about rapidly along the flower spikes and shoots, suck and feed on the plant sap. They are smaller in size, wingless and unable to fly or jump. The young ones moult their skin a few times during their growth and become adults in 10-15 days. The adult hoppers are small insects, about 3.0 mm. in length with a wedge-shaped body. The head is broader and the body gradually narrowing backwards. The legs are well developed, especially the hind legs. The general color is light greenish-brown. They are extremely active and can fly and hop around. They have a tubular, sucking mouthpart by which they puncture the tender plant parts and floral parts. The adults of Idioscopus clypealis are smaller, with two black spots on the prothorax and a few black spots on the front portion of the head, while those of Idioscopus niveoparsus are slightly bigger with three black spots on the prothorax and whitish, distinct cross bands on the light brownish forewings. The adults of Amritodes atkinsoni are bigger than the other two species, about 5.0 mm. in length, with two black spots on the prothorax. Two or more generations may appear during the flowering season of mango trees (Fig.71).

Light spectrum holds rich information about the world. The spectrum of natural illumination changes with daily cycle and objects differ in spectral reflection or emission properties. Like many other animals, insects use chromatic information to f ind favorable habitat, to efficiently locate food sources and to identify conspecific mates using the spectral information. Pollinating insects such as many species of bees and butterflies use their color vision to maximize success in foraging. They detect flowers, memorize the colors and patterns of rewarding flowers, and preferentially collect nectars from the flowers in their later visits. Visual guidance of behaviour is challenging when photons, the elementary particles of light, are scarce. To produce a reliable representation of the surroundings, the visual system must (i) ensure absorption of a sufficient number of photons into a photoreceptor, (ii) house photoreceptors that efficiently convert each photon absorption into a neural signal, and (iii) process these signals appropriately. Insects are a numerous and diverse class of arthropods that have evolved to occupy ecological niches from the brightest to the darkest.

Introduction

India has the distinction of being the largest producer of pulses in the world. Among the important pulse crops cultivated in the country are: chickpea, pigeonpea, lentil, mungbean, urdbean, fieldpea, rajmash and lathyrus. The pulse crops occupied an area of 22.85 million ha with a total production of 13.07 million tones and average productivity of 572 kg/ha. Being a high protein grain, pulses have special status in the diet, particularly for vegetarian population. Apart from being a good source of protein, they are also good source of energy, essential amino acids and vitamins in the daily diets of the people, especially of low-income group. Pulses have importance in sustainable agriculture by way of fixing atmospheric nitrogen in the soil.But with intensification of agriculture and introduction of irrigation and other facilities the area and production under pulses is declining so much so that per caput availability of pulses has declined from 69 g day-1 to about  36 g day^-1.

Introduction

Rice (Oryza sativa L.), one of the most important cereal crops of India, occupies 23.3 per cent of total cropped area of the country. Rice contributes 43 per cent of total food grain production and 46 per cent of total cereal production. It continues to play a vital role in the nation’s food grain supply. It is also a staple food of nearly half of the world population. Rice is primarily a high caloric food having protein content (6-17%) with high biological value and a low amount of fat (2-2.5%). B-group vitamins content in rice grains are at par with wheat, however, calcium content in rice is generally low. It ranks third after wheat and maize in terms of worldwide production. Asia accounts for 90 and 92% of the world’s rice area and production, respectively. Thus, rice production, consumption and trade are concentrated in Asia. Among the rice growing countries in the world, India has the largest areas under rice crop and ranks second in production next to China.

Introduction

Banana is the forth ranked agricultural crop in the world and first among fruits. A large number of pests and diseases threaten banana production. The major constraints in production are diseases and pests transmitted through the conventional planting materials. Although the average yield for bananas worldwide is over 40 t per hectare, production in India averages only 20 t per hectare. The nematode parasites are among the most important pests on commercial and subsistence banana production and their control remains difficult, as the nematodes are involved in the destruction of primary roots that disrupt the anchorage system resulting in toppling or uprooting of plants. The most widespread and important are burrowing nematode, Radopholus similes, some species of root lesion nematode, Pratylenchus coffeae and P. goodeyi, species of root knot nematode, Meloidogyne incognita and M. javanica; the spiral nematode, Helicotylenchus multicinctus, H. mucronatus and semi endo-parasitic nematode Rotytlenchus reniformis.

The cultivation of pineapple, Ananas comosus is prevalent in Kerala, Andhra Pradesh, Bihar and North eastern parts of the country. It is one of the choicest fruits all over the world because of its pleasant taste and flavour. Pineapple is a good source of vitamin A and B and fairly rich in vitamin C and minerals like calcium, magnesium, potassium and iron. It is also a source of bromelin, a digestive enzyme. In addition to being eaten fresh, the fruit can also be canned and processed in to different forms. The description of some of the major pests infesting pineapple are given hereunder:

Mealy bug, Dysmicoccus brevipes (Cockerell) (Pseudococcidae: Hemiptera)

It is a polyphagous pest and besides pineapple it infests banana, sugarcane, citrus, coffee and long pepper. These are small, oval and soft bodied sucking insects. The eggs are pink in colour but remain inside the female body. The first stage nymphs are called crawlers which moves to find a suitable spot for sucking of cell sap, thereafter they settle at a particular place. The adult is elliptical and bears 17 pairs of wax filaments (Plate 10h). The colour of the pest is pink but looks white due to white waxy covering. The mealy bug first infests root and later they are found

Introduction
Plant breeding and genetics are at the forefront of agricultural innovation, playing a crucial role in enhancing crop traits to meet the ever-growing demands for food, fiber, and fuel. This chapter delves into the scientific principles, methods, and modern advancements in plant breeding and genetics, providing a comprehensive understanding of how these disciplines contribute to global food security and environmental sustainability. The chapter begins by exploring the fundamental principles of plant breeding, including heredity, genetic variation, selection, and hybridization. These concepts form the foundation for developing new plant varieties that exhibit desirable traits such as improved yield, disease resistance, and environmental adaptability. The importance of genetic variation is emphasized as a key driver of plant improvement, with discussions on the sources of genetic variation, the role of germplasm resources, and the impact of genetic diversity on plant adaptation. As the chapter progresses, various breeding techniques and strategies are examined, including mass selection, pedigree breeding, backcrossing, and markerassisted breeding. These methods are crucial for developing new plant varieties that can withstand the challenges posed by climate change, pests, and diseases. The chapter also addresses the role of genomics in plant breeding, highlighting the significance of genomic selection, gene editing, and bioinformatics in accelerating the breeding process and enhancing crop traits. The chapter further explores the controversial topic of genetically modified organisms (GMOs), discussing the principles of genetic engineering, the rise of genetically modified crops, and the associated controversies and concerns. The importance of GMOs in addressing global food security and environmental challenges is also discussed, providing a balanced perspective on their potential benefits and risks. The chapter concludes by emphasizing the critical role of plant breeding and genetics in ensuring food security and combating global warming. By developing climate-resilient crop varieties, improving water efficiency, and enhancing disease and pest resistance, plant breeding and genetics can contribute to sustainable agricultural practices that reduce greenhouse gas emissions and conserve natural resources

21.1 Introduction

Plants and insects share a wonderful relationship. Both are dependent on each other at different levels and chemicals emitted by plants connect them to a large extent.  “Plants” contribute to a major share of occupancy on earth and makes several organisms such as insects & microbes and also humans to depend on them for their survival. This dependency leading to several interesting interactions between plants & insects which are often utilized by humans for their own benefit. Plants maintain incredible communication with their associated organisms. Since plants are rich banks of chemicals and constantly emit them in to its immediate environment which contributes in communication between insects and plants. Insects are the major organisms that have a long relation with the plants and there are several incredible ways how plants can interact with insect species.

Failure in timely diagnosis of diseases and other pests has often been responsible for devastating losses. Reducing crop losses by keeping pests at bay is crucial to food security. Plant clinic is an innovative paradigm which plays a vital role in assuring food security and ushering prosperity by providing timely diagnosis and rendering necessary advice to the growers, gardeners and other stakeholders for managing pest problem in India. Plant clinics are all about plant health. Though the major role of plant clinic lies in diagnostics and advisory, the activities of plant clinic extend beyond plant clinic, with emphasis on extension, working more closely with farmers and organizations involved in promoting food production. The role of plant clinics beyond diagnostics and advisory. These are:

The term “plant health” has two overlapping meanings. In the more specific meaning, plant health refers to plant quarantine, while in the less specific use, it covers all areas of plant protection, such as plant pest management, plant quarantine, and pesticide regulation and application.

Introduction

In agriculture and public health sectors, a variety of pesticides are still in uses that are toxic chemicals and having broad-spectrum actions. They kill target species but also harm the ecosystem seriously by affecting desirable organisms, thus, badly impairing prey-predator relationship. Most of these pesticides are persistent or non-biodegradable and hence exhibit biological magnification by accumulating at higher concentration in the organism, which are on the top of the food chain. The other drawbacks of repeated use of pesticides are eradication of natural enemies of pests, increased level of pesticide residues in soil, water, food and fodder crops, resistance of pests to pesticides and resurgence of minor pests in addition to the environmental pollution. It is clear that once used pesticide may persist, somewhere causing serious harm to the mankind and his ecosystem.

The increasing incidence of pesticide harms is fueling the need for new pesticides, which are toxicologically safe, more selective and efficacious and environment-friendly. Now the natural compounds, thus, have increasingly become the focus of those interested in discovery of pesticides. Tens of thousands of secondary products of plants have been identified and there are estimates that hundreds of thousands of these compounds exist. There is growing evidence that most of these compounds are involved in the interaction of plants with other species-primarily the defense of the plants from plant pests. Thus, these secondary compounds represent a large reservoir of chemical structures with biological activity. This resource is largely untapped for use as pest management agents^3, 4. The extraction of such chemicals from plants and derivatives of potent compounds are being encouraged all over the world under the Integrated Pest Management (IPM) approaches. The natural compounds and their synthetic derivatives are more selective in action, completely biodegradable and environment-friendly. In short, natural ways of pests control have already been established and are receiving much attention these days.

For effective and economic control of pests, besides selection of appropriate plant protection chemicals, application of the chemicals at the most vulnerable growth stage of the pests and use of chemicals at the correct dosage, selection of proper plant protection appliances to carry out the operation is also of vital importance, so as to ensure uniform application of the chemicals.

Plant protection chemicals are mostly used as sprays and dusts using sprayers and dusters respectively. However, in most of the cases spraying is preferred to dusting. Different types of sprayers and dusters are being used for these operations and in both, there are manually operated as well as power operated equipments and in sprayers there are both hydraulic and pneumatic types of sprayers.

The nature of the pesticide formulations to be used and the purpose for which they are used also determine the type of equipment to be used. Dusters are used for dusting insecticidal dust formulations. Sprayers are used for spraying insecticidal liquid formulations. Granular applicators are used to apply granular formulations. Fumigators are used to apply fumigants to fumigate godowns, warehouses, rat holes etc. Soil injectors are used to inject pesticides at a particular depth of soil under pressure. Flame throwers are used to throw f lames at specified targets.

Chemicals are commonly employed to manage plant diseases, pests, and weeds, but they are only effective if administered promptly once an infestation has been discovered. These chemicals must be sprayed, dusted, or misted over the ground and plants. Since the chemicals are expensive, it is important to have tools for applying them evenly and effectively. Crop Protection Products (CPP) like herbicides, pesticides, and fungicides work best when they are used at the right time during the crop’s most productive times. This problem is getting worse because there aren’t enough people to do the work. In this situation, the only choice that makes sense is to automate the application process. Most of the time, poisons are put on with dusters or sprayers. Dusting is the easier way to apply chemicals. It works best with movable equipment and usually only needs simple tools, but it is less effective than spraying because the dust doesn’t stick around as long. High volume spraying is usually efficient and reliable, but it is more expensive than low volume spraying, which fixes some of the problems with the first two methods while keeping the things that work well about them.

Introduction
Plant protection is a critical component of modern agriculture, aimed at safeguarding crops from diseases, pests, and weeds that can significantly impact yield and quality. Chapter 10 explores the science of plant protection, focusing on the various disciplines that contribute to maintaining healthy crops and ensuring food security. The chapter begins with an overview of plant pathology, the study of plant diseases caused by pathogens such as fungi, bacteria, viruses, and nematodes. Key principles of plant pathology are discussed, including the nature of plant diseases, their modes of transmission, and the factors that influence disease development. This section also highlights the importance of accurate disease diagnosis, which is essential for implementing effective prevention and control measures. Entomology, the study of insects and their interactions with plants, is another crucial aspect of plant protection covered in this chapter. The principles of entomology are examined, with a focus on the identification and management of insect pests that threaten crops. Various pest management strategies, including biological, chemical, and cultural methods, are explored, emphasizing the need for a holistic approach to pest control. Integrated Pest Management (IPM) is a central theme in plant protection, combining multiple strategies to manage pests in an environmentally sustainable manner. The chapter discusses the advantages of IPM, such as reduced reliance on chemical pesticides and minimized environmental impact, as well as the challenges associated with its implementation. Integrated Disease and Pest Management (IDPM) is also introduced, which integrates plant pathology and entomology principles to develop comprehensive management strategies that address both diseases and pests. The chapter further explores the role of pesticides in plant protection, including their benefits and potential risks. Safety measures for pesticide use are emphasized to protect both human health and the environment. Integrated Weed Management (IWM) is also discussed as an essential component of plant protection, with strategies for managing weeds that compete with crops for resources. The importance of plant protection sciences in food security is highlighted, particularly in the context of pest management, disease control, and weed management. These disciplines contribute to sustainable agriculture by enhancing crop yield and quality while promoting environmental sustainability.

Various insect and mite pests infest fruit and plantation crops in different stages of crop growth directly or indirectly causing significant losses, hence need their management. The major pests of different fruit and plantation crops, their identification characters, life history, nature of damage and symptoms alongwith its management practices are described crop wise:

Temperate fruits

Pome fruits and stone and nut fruits are mainly cultivated in the temperate regions, which usually requires chilling requirements. Among stone and nut fruits cherry, apricot, peach and plum are the main crops whereas among the nut fruits, walnut, almond are major crops which are a source of handsome income to the orchardists of those areas. The insect and mite pests of pome, stone and nut fruits are described hereunder:

Pomegranate, Punica granatum is a non-climacteric fruit belonging to smallest Botanical family Punicaceae. In India, Maharashtra is a leading producer of pomegranate followed by Gujarat. Around 90 pests are reported to feed on pomegranate plant out of which only few are of economic concern. The major insect pests and mites are discussed herewith:

Anar butterfly, Deudorix epijarbas (Moore); D. isocrates (Fabricius); (Lycaenidae: Lepidoptera)

Pomegranate fruit borer, commonly known as anar butterfly is a polyphagous direct pest found throughout the country. In addition to pomegranate, it also feeds on number of crops viz. litchi, citrus, loquat, guava, sapota, aonla etc. Even the wild pomegranate is heavily infested by the fruit borer. Two species namely Deudorix epijarbas and D. isocrates are reported feeding on pomegranate out of which the former is found in hilly terrain of Northern India whereas, the latter exists in the plains of the country. The eggs are glossy, light green and shiny. The larva is dark brown with short hairs and bears whitish patches all over the body (Plate 9d). The full fed larva measures 17-20mm. The adult of D. epijarbas is a brownish butterfly with an orange patch in the

Introduction

Pheromones are chemicals emitted by living organisms to send messages to individuals of the same species. The class most widely explored are the sex pheromones produced by female moths which are used to attract conspecific males for mating. Bombykol, the sex pheromone of the silk moth, was first synthesized in 1959.

During the past 40 years, pheromones of hundreds of insect species have been chemically elucidated, including the sex pheromone of the codling moth. Its main component is (E, E) 8, 10-dodecadien-1-o1, a primary alcohol containing a straight chain of 12 carbons and two conjugated double bonds. Other moth pheromones are hydrocarbons, epoxides, acetates or aldehydes. These molecules all vaguely resemble fatty acids, from which they are indeed biogenetically derived.

Most pheromones consist of blends of two or more chemicals which need to be emitted at exactly the right proportions to be biologically active. The female effluvia or sex gland can contain additional compounds which are related to the pheromone components and whose biological function is often unclear. On the other hand, many attractants of male moths have been discovered simply by field screening. In several cases it could later be shown that the attractant found with this technique was identical to the natural pheromone produced by the female. In most others, the composition of the true pheromone is still unknown.

Precision farming manages spatial and temporal variability within fields through targeted, data-driven interventions. Onion is particularly suited to precision management because its productivity and quality are sensitive to moisture, nutrients, environmental stress, pests and diseases. This chapter describes applications of GIS, GPS, variable-rate technology, IoT, cloud platforms, drones, remote sensing, multispectral imaging, smart sensors, artificial intelligence, automated systems and crop-response models. These technologies support soil assessment, field preparation, irrigation, fertilization, crop monitoring, stress detection, protection, yield estimation, harvesting and storage. Their potential to reduce input waste and improve profitability is considered alongside constraints involving investment costs, technical knowledge, connectivity, accessibility and data privacy.